System and method for storing data using software defined networks

ABSTRACT

A system for storing data includes a controller, an Ethernet switch and a storage device. The controller is configured to receive data routing instructions, and manage forwarding rules of a switch forwarding table to implement the data routing instructions. The Ethernet switch is configured to receive data, access the switch forwarding table, and route the data to the storage device using the switch forwarding table.

TECHNICAL FIELD

The present disclosure generally relates to systems and methods forstoring data, including storage systems and methods that implement asoftware defined network (SDN) to manage a switch forwarding table usedby an Ethernet switch.

BACKGROUND

Some comparative solid state drive (SSD) devices maintain legacy harddisk drive (HDD) mechanical features, including electrical features(e.g. SAS (Serial Attached SCSI (Small Computer System Interface)) andSATA (Serial Advanced Technology Attachment) buses) and softwarefeatures (e.g. drivers) for backward compatibility. Some comparativesystems and methods for routing data in, or to, such storage devices mayhave certain drawbacks. For example, as described in more detail herein,some comparative systems and methods involve a controller being in anincoming data path (an “in-path” controller), which can result in abottleneck due to the controllers limited data processing capabilities.Some other comparative systems and methods do not implement an in-pathcontroller, but also do not provide for virtualized management of datarouting. One or more of the embodiments described herein address theseand other issues.

BRIEF DESCRIPTION

According to certain aspects, one or more embodiments described hereinare directed to systems and methods for storing data, using an SDNmechanism to manage a switch forwarding table used by an Ethernet switchin a storage system. A controller of the storage system (e.g. acontroller not in a data path of incoming data to be routed) can manageswitch forwarding rules of the switch forwarding table, and an Ethernetswitch can route the incoming data using the switch forwarding table.This can provide for virtualization of the routing and storage process.

In one or more embodiments according to a first aspect, a system forstoring data includes a controller, an Ethernet switch and storagedevices. The controller is configured to receive data routinginstructions, and manage forwarding rules of a switch forwarding tableto implement the data routing instructions. The Ethernet switch isconfigured to receive data, access the switch forwarding table, androute the data to and from the storage devices using the switchforwarding table.

In one or more embodiments according to another aspect, a method forstoring data, includes receiving, by a controller of a storage system, arequest for a new namespace, selecting, by the controller, a first drivefor the new namespace, and creating, by the controller, a first physicalnamespace on the first drive as the new namespace. The method furtherincludes assigning, by the controller, a virtual internet protocol (IP)address to the first physical namespace, and modifying or creating, bythe controller, one or more entries of a switch forwarding tableaccessible to a switch to cause the switch to route data correspondingto the virtual IP address to the first physical namespace.

In one or more embodiments according to another aspect, a method forstoring data includes receiving, by a controller of a storage system, arequest to migrate data from a first physical namespace to a secondphysical namespace, the first namespace corresponding to a virtual IPaddress, and selecting, by the controller of the storage system, asource Ethernet drive on which the first physical namespace resides, thesource Ethernet drive comprising one or more Ethernet controllersconfigured to functions as a non-volatile memory express over fiber(NVMeoF) initiator. The method further includes selecting, by thecontroller of the storage system, a target Ethernet drive comprising oneor more Ethernet controllers configured to functions as an NVMeoFtarget, creating, by the controller of the storage system, the secondphysical namespace on the target Ethernet drive, transmitting, by thecontroller of the storage system, a command to the source Ethernet driveto copy data from the first physical namespace to the second physicalnamespace of the target Ethernet drive using an Ethernet switch, andsetting, by the controller of the storage system, the virtual IP addressto correspond to the second physical namespace.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A shows a block diagram of a comparative data storage systemincluding a controller in a data path of incoming data to be routed.

FIG. 1B shows a block diagram of another comparative data storage systemincluding a controller in a data path of incoming data to be routed.

FIG. 1C shows a block diagram of a comparative data storage system thatincludes a network interposer.

FIG. 2 shows a block diagram of a data storage system according to oneor more embodiments of the present disclosure.

FIG. 3A shows a method for routing data to a new namespace according toone or more embodiments of the present disclosure.

FIG. 3B shows a method for mirrored routing of data according to one ormore embodiments of the present disclosure.

FIG. 4 shows a method for migrating data according to one or moreembodiments of the present disclosure.

FIG. 5 is a block diagram showing a system for copying data according toone or more embodiments of the present disclosure.

DETAILED DESCRIPTION

The embodiments described herein provide for certain improvements,including providing for virtualization of routing control of a storagesystem and use of a controller that is not in-path. One or more of theembodiments provided herein implement an SDN to control routing in astorage system. Generally speaking, an SDN separates control functionsfrom data functions for networking devices (e.g. packet switches, localarea network (LAN) switches, and routers) using an ApplicationProgramming Interface (API) to implement communications between thecontrol functions and the data functions. In some comparative storagesystems, network devices handle both data and control functions, andsuch network devices can make it difficult to implement vitualization(e.g. for substantial administrator control of data routing, networkinfrastructure, and other operations through a virtual network) on alarge scale.

In some SDNs, a central controller performs many high level functions,such as security checks, naming, policy declaration, and routing. Indata routing, for example, this can allow for offloading the high levelfunctions to the controller, and can allow for implementing relativelysimple switches. For example, switches (e.g. Ethernet switches) canreference flow tables or “switch forwarding tables” to direct incomingdata, and the controller (or a plurality of controllers) can manage theswitch forwarding tables to control routing (e.g. to implement anadministrator's instructions). The storage systems and methods describedherein, which can provide for having one or more central controllersmanage the high level functions of a routing system, can allow forvirtualized control even on large, scaled-out systems.

In one or more embodiments described herein, the SDN implements anOpenFlow specification (as defined and occasionally updated in theOpenFlow Switch Specification, regularly published by the OpenNetworking Foundation as of the date of filing of this specification).OpenFlow includes a protocol for communication between SDN controllersand network devices, and a specification as to a logic structure of thenetwork switch functions, and can be used to implement at least some ofthe systems and methods described herein. OpenFlow allows for use of aswitch forwarding table, as described in more detail below in referenceto FIG. 2. In some embodiments, other protocols and/or logic structurescan be used in place of, or in addition to, OpenFlow.

Referring now to FIG. 1A, a comparative system 102 for storing dataincludes an Ethernet network interface controller (NIC) 104, acontroller 106, a mapping table 108, a local bus 110, and a plurality ofdrives 112. The comparative system 102 may be, for example, a datastorage system in which data is stored, and retrieved from, the drives112. The comparative system 102 provides for a data path whereinincoming data flows from the Ethernet NIC 104 to the controller 106,which routes the data to one or more of the drives 112 using the localbus 110. The comparative system 102 may be implemented in, for example,a data center, a local data network, a computer system, or in any otherappropriate system or network.

The Ethernet NIC 104 can function as an interface between the system 102and an external device or network, and can receive incoming data andpass that data to the controller 106. The Ethernet NIC 104 canimplement, for example, an internet small computer systems interface(iSCSI) or fiber channel (FC) port.

The controller 106 may be, for example, a centralized controllerconfigured to receive out-of-band management including, for example,data routing instructions or policies. The controller 106 can update amapping table 108 (e.g. stored in computer memory accessible to thecontroller 106) according to the data routing instructions or policies.The controller 106 can receive data from the Ethernet NIC 104, and canprocess the data (e.g. can implement transport protocol decapsulationand storage processing), reference the mapping table 108, and route thedata accordingly. The controller 106 can be configured to intercept astorage layer of the incoming data and to manipulate address space orthe data itself to provide storage functionality. For example, addressmanipulation can be striping (e.g. redundant array of independent disks“0” (RAID-0)), mirroring (e.g. RAID-1), or any other storagevirtualization functionality.

The local bus 110 can be used by the controller 106 to route data fromthe controller 106 to one or more of the drives 112, or to route databetween the drives 112, and can provide for fan-out functionality forthe controller 106. The local bus may be SAS or SATA compatible.

The drives 112 (e.g. storage drives) may each include a SATA or SASinterface 114, a controller 116, and NAND type flash memory 118 (or anyother appropriate type of computer memory).

Among other things, the present Applicant recognizes that theabove-described processing and routing by the controller 106 canconstitute a bottleneck in storage efficiency. The controller 106 is inthe data path and must perform processing on the incoming data prior torouting the data. The controller 106 may be configured for multiplefunctionalities, including processing the out-of-band management andupdating the mapping table 108. As such, the controller 106 may lacksome of the advantages of a specialized routing device that is notconfigured for such processing. Thus, the comparative system 102 may beless efficient or effective than desired.

Refer now to FIG. 1B, which shows a comparative storage system 120 thatimplements a peripheral component interconnect express (PCIe) switch.The comparative system 120 includes an Ethernet NIC 104, a controller106, and a mapping table 108 (e.g. similar to, or the same as, thosecomponents described above in reference to FIG. 1A), as well as a PCIeswitch 122 and a plurality of non-volatile memory express (NVMe) drives124. The NVMe drives 124 may each include a PCIe interface 126, acontroller 128, and NAND-type memory 130.

The comparative system 120 offers some improvements over the comparativesystem 102 by implementing the PCIe switch 122 and the NVMe drives 124,which can provide for between performance, capacity, and/or density. Forexample, the NVMe drives 124 may have improved form factors and theirPCIe interface 126 can provide for higher bandwidth. Furthermore, theNVMeoF protocol can be used to further increase performance.

However, the controller 106 of the comparative system 120 is still inthe data path. As discussed above, the present Applicant recognizes thatthis can be a bottleneck in terms of the performance of the comparativesystem 120 (e.g. because the non-specialized controller 106 is used toprocess the incoming data).

Referring now to FIG. 1C, another comparative approach is to implementan Ethernet drive 132 or an Ethernet drive 142 with an interposer. Asshown in FIG. 1C, the Ethernet drive 132 includes an Ethernet NIC 134, acontroller 136 configured for NVMeoF, a controller flash translationlayer (FTL) 138, and a NAND-type memory 140.

The Ethernet NIC 134 is an interface between the Ethernet drive 132 anda host. Thus, the host can access the Ethernet drive 132 directly. Toimplement this, the controller 136 is configured for NVMeoFfunctionality. The controller 136 makes use of the controller FTL 138,which maps host side or file system logical block addresses to physicaladdresses of the NAND-type memory 140. Thus, NVMeoF transport can beoffloaded to the Ethernet drive 132 itself, and hosts can access theEthernet drive 132 directly without the overhead of computation requiredfor protocol translation.

Referring now to the Ethernet drive 142, the Ethernet Drive 142 includesa network interposer 144 and an NVMe drive 146. The network interposer144 can include an Ethernet NIC 148 that serves as an interface betweenthe Ethernet drive 142 and a host, a controller 150 configured forNVMeoF protocol, and a PCIe interface 152. The NVMe drive 146 includesanother PCIe interface 152 configured to communicate with the PCIeinterface 152 of the network interposer, a controller configured toimplement PCIe 154, a controller FTL 156, and a NAND-type memory 158.Thus, an NVMe drive 146 can be implemented with a network interposer 144that provides for a host to communicate directly with the Ethernet drive142. Read and write functionality can thus be implemented with NVMeoF.

However, the present Applicant recognizes that the configurations shownin FIG. 1C for the Ethernet drive 132 and the Ethernet drive 142 can becomputationally demanding on the NVMeoF-configured controllers. As inthe systems shown in FIG. 1A and FIG. 1B, the Ethernet drive 132 and theEthernet drive 142 implement controllers that are in an incoming datapath. As such, bottlenecks of the type discussed above may occur as datapasses through those controllers.

FIG. 2 shows an example data storage system 202 according to one or moreembodiments of the present disclosure. In one or more embodiments, thedata routing system 202 includes a controller 204, a mapping table 206,an Ethernet switch 208, a switch forwarding table 210, and a pluralityof Ethernet drives 212. Other embodiments contain additional or fewercomponents than shown in FIG. 2. The data storage system 202 providesfor a controller outside of an incoming data path that manages a switchforwarding table using OpenFlow, and an Ethernet switch that referencesthe switch forwarding table to route the incoming data to one or moreEthernet drives. This configuration provides for out-of-band managementand virtualized control of the storage system via the controller, andprovides for improved performance by implementing the dedicated Ethernetswitch and by omitting use of a centralized controller in the data path.

In one or more embodiments, the controller 204 can be configured toreceive instructions or commands from an administrator or externaldevice, network, or host. These instructions or commands can constituteout-of-band management. The controller 204 can provide for centralizedcontrol of the data storage system 202 through which routing can bemanaged externally. Thus, virtualized management of the data storagesystem 202 can be implemented, allowing an administrator significantcontrol over data routing and providing for improved management oflarge-scale systems by implementing policies that affect system-widerouting through the centralized controller 204.

The instructions received by the controller 204 may include reference toa virtual IP address, and the controller 204 can be configured toreference and manage the mapping table 206 (which is, for example, adata structure stored in computer memory accessible to the controller204) to determine a physical address that corresponds to the virtual IPaddress. Each virtual IP address corresponds to a virtual namespace. Anamespace can be a quantity of non-volatile memory that may be formattedinto logical blocks. When formatted, a namespace of size n is acollection of logical blocks with logical block addresses from 0 to(n−1). A namespace may also be referred to as a block device, or as avolume of a disk, drive, or other memory device. The physical addressmay specify one or more of the Ethernet drives 212, and may specify oneor more namespaces residing on the specified one or more of the Ethernetdrives 212. Thus, by using the mapping table 206 the controller 204 canimplement policies or instructions related to physical addresses andnamespaces that correspond to virtual IP addresses referenced by anexternal host, and the external host need not necessarily know thecorresponding physical address and namespace.

In one or more embodiments, the controller 204 is configured to managethe switch forwarding table 210 to implement the received instructionsor policies. For example, the controller 204 may use an SDN mechanismsuch as OpenFlow to add, delete, or modify entries in the switchforwarding table 210. OpenFlow has a large set of matching rules thatcan be implemented, including wild cards for matching IP addresses andMAC addresses, protocol, or port numbers. OpenFlow actions includepacket forwarding to a specific switch port, dropping the packet,sending the packet to the controller 204, or modifying the packet (e.g.changing the source/destination Mac/IP addresses). Alternatively, thecontroller 204 may use another policy to manage the switch forwardingtable 210. Thus the controller 204 need not directly control theEthernet switch 208, although in some embodiments such control can beimplemented. The controller 204 can specify an expiry time for entriesin the switch forwarding table 210. The controller 204 can update,delete, or extend the validity of the existing rules at any time.

In one or more embodiments, the controller 204 can also be configured tocommunicate with one or more of the Ethernet drives 212 via I²C. Forexample, the controller 204 can implement an NVMe-MI configuration tocreate, delete, or modify namespaces on the one or more Ethernet drives212, or can gather log information from the one or more Ethernet drives212.

In one or more embodiments, the Ethernet switch 208 may be configured toreceive incoming data (e.g. may be in the incoming data path), and maybe configured to reference the switch forwarding table 210 to determinehow to route or otherwise manage the incoming data. In some embodiments,the Ethernet switch 208 is not configured to directly communicate withthe controller 204. Based on information referenced in the switchforwarding table 210, the Ethernet switch 208 may route data to one ormore appropriate Ethernet drives 212. The Ethernet switch may be aspecialized device configured to perform at least the functionsdescribed herein, and may thus efficiently route incoming data withlittle processing required beyond referencing the switch forwardingtable 210. In one or more embodiments, the Ethernet switch 208 is notconfigured to modify entries of the switch forwarding table 210.

In one or more embodiments, the switch forwarding table 210 may be adata structure stored in computer memory that stores one or morematching rules and one or more corresponding action lists. The switchforwarding table 210 may be configured according to OpenFlowspecifications. In one or more embodiments, modification of entries inthe switch forwarding table 210 may be restricted (e.g. restricted tothe controller 204), and the switch forwarding table 210 may bereferenced by (e.g. may allow read functionality to) the Ethernet switch208.

The switch forwarding table 210 may include matching rules for matchingincoming data with one or more action lists. For example, the matchingrules may specify one or more headers or content within a header ofincoming data. The matching rules may be associated with one or moreaction lists that include a list of actions to be taken for data thatsatisfies the corresponding matching rules. For example, the action listcan include a plurality of actions that are to be performed in sequencewith the matched data. By way of example, a header of incoming data mayreference a virtual IP address. The Ethernet switch 208 may referencethe switch forwarding table 210 and determine that the virtual IPaddress satisfies a matching rule of the switch forwarding table. TheEthernet switch 208 may determine that a corresponding action list forthe matching rule includes an action of storing the data at a particularphysical address (e.g. in a particular namespace of a particularEthernet drive 212). The Ethernet switch 208 may responsively store theincoming data at the specified particular physical address. Thus, theEthernet switch can implement routing by referencing the switchforwarding table 210, and need not necessarily communicate directly withthe controller 204.

In one or more embodiments, a plurality of Ethernet switches 208 may beimplemented. The plurality of Ethernet switches 208 may reference a sameswitch forwarding table 210, or may reference respective switchforwarding tables 210 of a plurality of switch forwarding tables 210.The controller 204 may be configured to modify or create entries of theplurality of switch forwarding tables 210 using OpenFlow.

In one or more embodiments, the Ethernet drives 212 can each include anEthernet NIC 214, a controller 216, and a NAND-type memory 218. TheEthernet NIC 214 can be configured to function as an interface betweenthe Ethernet drive 212 and the Ethernet switch 208. The controller 216can perform local functions, including read/write functions to theNAND-type memory 218. In one or more embodiments, the Ethernet drives212 can be configured to communicate and/or to transfer data betweeneach other (e.g. through the Ethernet switch 208). While the presentlydescribed embodiments implement an Ethernet drive 212 and an Ethernetswitch 208, other types of drives and switches can be implemented inconjunction with the controller 204 and the switch forwarding table 210.

Thus configured, the data storage system 202 can provide for efficientrouting and storage of data and for centralized control of the datastorage system 202 through the controller 204. This can provide forimproved performance and for virtualization of control of the datastorage system 202.

Refer now to FIG. 3A, which shows an example method for creating anamespace on one of the Ethernet drives 212 of the data storage system202. In a brief overview, the method includes steps 302-312. At step302, the controller 204 receives a request to create a new namespacefrom an external host or device. At step 304, the controller 204 selectsan Ethernet drive 212 for the new namespace. At step 306, the controller204 creates a physical namespace on the Ethernet drive 212 as the newnamespace. At step 308, the controller assigns a virtual IP address tothe physical namespace. At step 310, the controller modifies or creates(e.g. using a SDN mechanism such as OpenFlow) one or more entries of theswitch forwarding table to cause the Ethernet switch 208 to route datacorresponding to the virtual IP address to the physical namespace. Atstep 312, the controller provides the virtual IP address to the devicethat requested the new namespace. Other embodiments contain additionalor fewer steps than shown in FIG. 3A.

In more detail, at step 302, the controller 204 receives a request for anew namespace from a host or an external device or network. The requestmay include specifications for the namespace, such as a size of thenamespace or a range of acceptable sizes, or a particular drive in whichto create the namespace, or one or more types of acceptable drives inwhich to create the namespace. The request may specify a quality ofservice (QoS) and/or a service-level agreement (SLA). The request may bereceived via an interface provided to an administrator that allows forvirtualized control of the data storage system 202.

At step 304, the controller 204 selects an Ethernet drive 212 for thenew namespace. The controller may select the Ethernet drive 212 tosatisfy requirements of the request received at step 302. For example,the controller 204 may reference a list of drives and associatedcharacteristics (e.g. interface type, available space, memory type), andselect a suitable Ethernet drive 212 based on the associatedcharacteristics. If more than one drive satisfies the requirements ofthe request, the controller 204 may select a drive in accordance with apolicy (e.g. a predetermined policy or a policy specified in therequest).

At step 306, the controller 204 creates a physical namespace on theselected Ethernet drive 212 as the new namespace. The controller 204 maydo this by implementing I²C functionality that allows the controller 204to communicate with the Ethernet drive 212. The controller 204 mayimplement NVMe-MI protocol to create the physical namespace.

At step 308, the controller 204 assigns a virtual IP address to thephysical namespace. The assignment may be done via L3 (layer 3 of theopen systems interconnection (OSI) model) configuration of the Ethernetswitch 208. For example, the controller 204 can use border gatewayprotocol (BGP) to route the virtual IP address to the physicalnamespace. Thus traffic to the virtual IP address may be forwarded tothe physical namespace. This mapping may be stored in the mapping table206. The virtual IP address may be used by an external host or device toreference the physical namespace and to direct routing of data to orfrom the physical namespace. This provides for virtualization of thedata storage system 202 through the centralized controller 204.

At step 310, the controller 204 modifies or creates one or more entriesof the switch forwarding table 210 using OpenFlow. Each entry of theswitch forwarding table 210 may include a matching rule and acorresponding action list that includes one or more actions. Thecontroller 204 may create an entry that includes a matching rule thatreferences the assigned virtual IP address, and an action list that mayinclude, for example, routing data to the physical namespace orretrieving data from the physical namespace (e.g. implementing read orwrite functions on the namespace). Alternatively, the controller 204 maymodify an existing entry in the switch forwarding table 210 to achievethe same effect.

At step 312, the controller 204 provides the virtual IP address to theexternal host or device that requested the new namespace. Thus, theexternal host or device can reference the virtual IP address in othercommunications to interact with the created physical namespace,providing for virtualized control over the data storage system 202.

Refer now to FIG. 3B, which shows an example method for creating mirrornamespaces using the data storage system 202. The method includes steps320-330. In a brief overview, at step 320, the controller 204 receives arequest from an external host or device to create new mirrorednamespaces. At step 322, the controller 204 selects a first Ethernetdrive 212 and creates a first physical namespace on the first Ethernetdrive 212. At step 324, the controller 204 selects a second Ethernetdrive 212 and creates a second physical namespace on the second Ethernetdrive 212. At step 326, the controller 204 assigns a virtual IP addressto both the first physical namespace and the second physical namespace.At step 328, the controller 204 modifies or creates one or more entriesof the switch forwarding table 210 to cause the Ethernet switch 208 toroute write communications to both namespaces and to route readcommunications to one of the name spaces. At step 330, the controller204 provides the virtual IP address to the external host or device thatrequested the new mirrored namespaces. Other embodiments containadditional or fewer steps than shown in FIG. 3B.

In more detail, at step 320, the controller 204 receives a request froman external host or device to create new mirrored namespaces. Therequest may include specifications for the namespaces, such as a size ofthe namespaces or a range of acceptable sizes, or particular drives inwhich to create the namespaces, or one or more types of acceptabledrives in which to create the namespaces. The request may specify aquality of service (QoS) and/or a service-level agreement (SLA). Therequest may be received via an interface provided to an administratorthat allows for virtualized control of the data storage system 202.

At step 322, the controller 204 selects a first Ethernet drive 212 andcreates a first physical namespace on the first Ethernet drive 212. Thecontroller may select the first Ethernet drive 212 to satisfyrequirements of the request received at step 320. For example, thecontroller 204 may reference a list of drives and associatedcharacteristics (e.g. interface type, available space, memory type), andselect a suitable Ethernet drive 212 based on the associatedcharacteristics. If more than one drive satisfies the requirements ofthe request, the controller 204 may select a drive in accordance with apolicy (e.g. a predetermined policy or a policy specified in therequest). The controller 204 then creates a first physical namespace onthe first Ethernet drive 212 as a new namespace. The controller 204 maydo this by implementing I²C functionality that allows the controller 204to communicate with the Ethernet drive 212. The controller 204 mayimplement NVMe-MI protocol to create the first physical namespace.

At step 324, the controller 204 selects a second Ethernet drive 212 andcreates a second physical namespace on the second Ethernet drive 212.The controller may select the second Ethernet drive 212 to satisfyrequirements of the request received at step 320. For example, thecontroller 204 may reference a list of drives and associatedcharacteristics (e.g. interface type, available space, memory type), andselect a suitable Ethernet drive 212 based on the associatedcharacteristics. If more than one drive satisfies the requirements ofthe request, the controller 204 may select a drive in accordance with apolicy (e.g. a predetermined policy or a policy specified in therequest). The controller 204 then creates a second physical namespace onthe second Ethernet drive 212 as a new namespace. The controller 204 maydo this by implementing I²C functionality that allows the controller 204to communicate with the Ethernet drive 212. The controller 204 mayimplement NVMe-MI protocol to create the second physical namespace.

At step 326, the controller 204 assigns a virtual IP address to both thefirst physical namespace and the second physical namespace. Theassignment may be done via L3 (layer 3 of the open systemsinterconnection (OSI) model) configuration of the Ethernet switch 208.For example, the controller 204 can use border gateway protocol (BGP) toroute the virtual IP address to the physical namespaces. Thus traffic tothe virtual IP address may be forwarded to the physical namespaces. Inother embodiments, the controller 204 can configure the Ethernet switch208 for port mirroring to a secondary address via L2 (layer 2 of the OSImodel) configuration. This mapping may be stored in the mapping table206. The virtual IP address may be used by an external host or device toreference the physical namespace and to direct routing of data to orfrom the physical namespaces. This provides for virtualization of thedata storage system 202 through the centralized controller 204.

At step 328, the controller 204 modifies or creates one or more entriesof the switch forwarding table 210, using OpenFlow, to cause theEthernet switch 208 to route write communications to both namespaces andto route read communications to one of the name spaces. Each entry ofthe switch forwarding table 210 may include a matching rule and acorresponding action list that includes one or more actions. Thecontroller 204 may create an entry that includes a matching rule thatreferences the assigned virtual IP address and that specifies a readcommand, and a corresponding action list that may include, for example,requesting data from one of the first physical namespace and the secondphysical namespace. The controller 204 may select the first physicalnamespace or the second physical namespace randomly (e.g. by referencingan output of a random number generator or by referencing a clock), ormay select the physical namespace according to some policy (e.g. a roundrobin policy). The controller 204 may also create an entry that includesa matching rule that references the assigned virtual IP address and thatspecifies a write command, and a corresponding action list that mayinclude, for example, storing data on both of the first physicalnamespace and the second physical namespace.

At step 330, the controller 204 provides the virtual IP address to theexternal host or device that requested the new mirrored namespaces.Thus, the external host or device can reference the virtual IP addressin other communications to read or write to the created mirrorednamespaces, providing for virtualized control over the data storagesystem 202.

Refer now to FIG. 4, which shows an example method for migrating datausing the data storage system 202. The method includes the steps 402-412(with step 412 being optional). In a brief overview, at step 402, thecontroller 204 receives a request from an external host or device tomigrate data from a first physical namespace corresponding to a virtualIP address to a second physical namespace. At step 404, the controller204 selects a source Ethernet drive 212 on which the first physicalnamespace resides, and selects a target Ethernet drive 212. At step 406,the controller 204 creates the second physical namespace on the targetEthernet drive. At step 408, the controller 204 transmits a command tothe source Ethernet drive 212 to copy data from the first physicalnamespace to the second physical namespace of the target Ethernet drive212 using the Ethernet switch 208. At step 410 the controller 204 setsthe virtual IP address to correspond to the second physical namespace.Optionally, at step 412, the controller 204 transmits a command to thesource Ethernet drive 212 to delete the migrated data from the firstphysical namespace. Other embodiments contain additional or fewer stepsthan shown in FIG. 4.

In more detail, at step 402, the controller 204 receives a request froman external host or device to migrate data from a first physicalnamespace corresponding to a virtual IP address to a second physicalnamespace. The request may include specifications for the secondphysical namespace, such as a size of the namespace or a range ofacceptable sizes, or a particular drive in which to create the secondphysical namespace, or one or more types of acceptable drives in whichto create the second physical namespace. The request may specify aquality of service (QoS) and/or a service-level agreement (SLA). Therequest may be received via an interface provided to an administratorthat allows for virtualized control of the data storage system 202.

At step 404, the controller 204 selects a source Ethernet drive 212 onwhich the first physical namespace resides, and selects a targetEthernet drive 212. The controller may select the target Ethernet drive212 to satisfy requirements of the request received at step 402, and tohave at least enough available space to accommodate the data to bemigrated. For example, the controller 204 may reference a list of drivesand associated characteristics (e.g. interface type, available space,memory type), and select a suitable target Ethernet drive 212 based onthe associated characteristics. If more than one drive satisfies therequirements of the request, the controller 204 may select a drive inaccordance with a policy (e.g. a predetermined policy or a policyspecified in the request).

At step 406, the controller 204 creates the second physical namespace onthe target Ethernet drive. The controller 204 may do this byimplementing I²C functionality that allows the controller 204 tocommunicate with the target Ethernet drive 212. The controller 204 mayinstruct the target Ethernet drive 212 to create the second physicalnamespace to be at least large enough to accommodate the data to bemigrated.

At step 408, the controller 204 transmits a command to the sourceEthernet drive 212 to copy data from the first physical namespace to thesecond physical namespace of the target Ethernet drive 212 via theEthernet switch 208. For example, the controller 204 instructs thesource Ethernet drive 212 to transmit the data to be migrated to thetarget Ethernet drive 212 via Ethernet switch 208 along with anidentifier (e.g. contained in a header) that identifies the migrationprocess and identifies a physical address of the target Ethernet drive212. The controller 204 may do this by implementing I²C functionalitythat allows the controller 204 to communicate with the source Ethernetdrive 212. The source Ethernet drive 212 may transmit the data to bemigrated to the specified physical address of the target Ethernet drive212 via the Ethernet switch, responsive to receiving the instructionsfrom the controller 204.

At step 410, the controller 204 sets the virtual IP address tocorrespond to the second physical namespace. The controller 204 may setthe virtual IP address to correspond to the second physical namespace byupdating the switch forwarding table 210. The virtual IP address may beused by an external host or device to reference the second physicalnamespace and to direct routing of data to or from the second physicalnamespace. This provides for virtualization of the data storage system202 through the centralized controller 204.

Optionally, at step 412, the controller 204 transmits a command to thesource Ethernet drive 212 to delete the migrated data from the firstphysical namespace. This can free up space on the source Ethernet drive212 following the data migration. In other embodiments, a copyfunctionality can be implement by performing steps 402-410 and by notdeleting the data on the source Ethernet drive 212.

Thus, the data storage system 202 can provide for virtualized controlover an efficient method of migrating data (or copying data). The databeing migrated or copied need not pass through the controller 204.

Refer now to FIG. 5, which shows an example system for performing acopying or data migration process, such as the process shown in FIG. 4and described above. The system includes an Ethernet switch 502 (whichmay be similar to, or the same as, the Ethernet switch 208), a switchforwarding table 514 (which may be similar to, or the same as, theswitch forwarding table 210), and two Ethernet drives 504. The Ethernetdrives 504 may each include an Ethernet NIC 506, a controller FTL 510,and a NAND-type memory 512. Other embodiments contain additional orfewer components than shown in FIG. 5.

One of the Ethernet drives 504, functioning as a target drive, includesa controller 508 configured for NVMeoF functionality. The controller 508is configured to act as a target for a copy or migration process (e.g.to receive and store the copied or migrated data). The other Ethernetdrive 504, functioning as a source drive, includes a controller 508′configured for NVMeoF functionality. The controller 508′ is configuredto act as an initiator for a copy or migration process (e.g. to transmitthe data to be copied or migrated to the Ethernet switch 502, along withan identifier of the copy or migration process). In someimplementations, both the Ethernet drives 504 include controllersconfigured to functions as both initiators and as targets. Thecontroller 204 may instruct the initiator Ethernet drive 504 to initiatean NVMeoF session with the target Ethernet drive 504.

This provides for a flexible system in which data can be readily copiedor migrated between Ethernet drives as needed. Such Ethernet drives canbe implemented in the data storage system 202.

While the present disclosure has been described and illustrated withreference to specific embodiments thereof, these descriptions andillustrations are not limiting. It should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of thepresent disclosure as defined by the appended claims. The illustrationsmay not necessarily be drawn to scale. There may be distinctions betweenthe artistic renditions in the present disclosure and the actualapparatus due to manufacturing processes and tolerances. There may beother embodiments of the present disclosure which are not specificallyillustrated. The specification and the drawings are to be regarded asillustrative rather than restrictive. Modifications may be made to adapta particular situation, material, composition of matter, method, orprocess to the objective, spirit and scope of the present disclosure.All such modifications are intended to be within the scope of the claimsappended hereto. While the methods disclosed herein have been describedwith reference to particular operations performed in a particular order,it will be understood that these operations may be combined,sub-divided, or re-ordered to form an equivalent method withoutdeparting from the teachings of the present disclosure. Accordingly,unless specifically indicated herein, the order and grouping of theoperations are not limitations.

What is claimed is:
 1. A system for storing data, comprising: acontroller that is configured to: receive data routing instructions froman external entity, wherein the data routing instructions configure howdata is stored in the system without reference to physical addresses ofstorage devices in the system; and manage forwarding rules of a switchforwarding table in terms of physical addresses to implement the datarouting instructions; an Ethernet switch that is configured to: receivedata; access the switch forwarding table; and route the data using thephysical addresses in the switch forwarding table; and one or moreEthernet drives, wherein the Ethernet switch is configured to route thedata using the switch forwarding table for storing the data in at leastone of the Ethernet drives.
 2. The system of claim 1, wherein thecontroller is further configured to communicatively connect to andconfigure the one or more Ethernet drives.
 3. The system of claim 2,wherein the controller is further configured to communicatively connectto the one or more Ethernet drives using inter-integrated circuit (I²C)connectivity, or to configure the one or more Ethernet drives using anon-volatile memory express management interface (NVMe-MI).
 4. Thesystem of claim 2, wherein the controller is further configured toconfigure the one or more Ethernet drives to create a physicalnamespace, to determine a virtual address corresponding to the physicalnamespace, and to store an indication of the correspondence of thevirtual address and the physical namespace in a mapping table.
 5. Thesystem of claim 1, wherein the controller is further configured toreceive out-of-band data routing instructions.
 6. The system of claim 1,wherein the controller is further configured to manage the forwardingrules of the switch forwarding table by instructing insertion ordeletion of forwarding rules.
 7. The system of claim 1, wherein thecontroller is further configured to set an expiry date for one or moreof the forwarding rules of the switch forwarding table.
 8. The system ofclaim 1, wherein the controller is further configured to manage theforwarding rules of the switch forwarding table using an OpenFlowprotocol.
 9. The system of claim 1, wherein the switch forwarding tableincludes one or more matching rules and one or more action listsrespectively corresponding to the one or more matching rules.
 10. Thesystem of claim 9, wherein the one or more actions includes at least oneof forwarding a data packet to a specific switch port, dropping the datapacket, sending the data packet to the controller, or modifying the datapacket.
 11. The system of claim 9, wherein the Ethernet switch isfurther configured to modify at least one of the one or more matchingrules or at least one of the one or more action lists based on aninstruction received from the controller.
 12. The system of claim 1,wherein the controller is further configured to receive out-of-band datarouting instructions, and the Ethernet switch is further configured toreceive the data and to route the data to the one or more Ethernetdrives without passing the data through the controller.
 13. The systemof claim 1, wherein the data is first data, the Ethernet switch is afirst Ethernet switch, and the system further comprises a secondEthernet switch configured to: receive second data; access a secondswitch forwarding table; and route the second data using the secondswitch forwarding table.
 14. A method for storing data in a systemcomprising Ethernet drives, comprising: receiving from an externalentity, at a controller, data routing instructions that configure howdata is stored in the system without reference to physical addresses ofstorage devices in the system; managing, by the controller, forwardingrules of a switch forwarding table in terms of physical addresses toimplement the data routing instructions; receiving data at an Ethernetswitch; accessing, by the Ethernet switch, the switch forwarding table;routing, by the Ethernet switch, the data using the physical addressesin the switch forwarding table to one or more Ethernet drives; andstoring the data in the one or more Ethernet drives.